These functions return or act on a user credential, ucred_t. User credentials are returned by various functions and describe the creden-
tials of a process. Information about the process can then be obtained by calling the access functions. Access functions can fail if the
underlying mechanism did not return sufficient information.
The ucred_get() function returns the user credential of the specified pid or NULL if none can be obtained. A pid value of P_MYID returns
information about the calling process. The return value is dynamically allocated and must be freed using ucred_free().
The ucred_geteuid(), ucred_getruid(), ucred_getsuid(), ucred_getegid(), ucred_getrgid(), and ucred_getsgid() functions return the effective
UID, real UID, saved UID, effective GID, real GID, saved GID, respectively, or -1 if the user credential does not contain sufficient infor-
mation.
The ucred_getgroups() function stores a pointer to the group list in the gid_t * pointed to by the second argument and returns the number
of groups in the list. It returns -1 if the information is not available. The returned group list is valid until ucred_free() is called on
the user credential given as argument.
The ucred_getpid() function returns the process ID of the process or -1 if the process ID is not available. The process ID returned in a
user credential is only guaranteed to be correct in a very limited number of cases when returned by door_ucred(3C) and ucred_get(). In all
other cases, the process in question might have handed of the file descriptor, the process might have exited or executed another program,
or the process ID might have been reused by a completely unrelated process after the original program exited.
The ucred_getprojid() function returns the project ID of the process or -1 if the project ID is not available.
The ucred_getzoneid() function returns the zone ID of the process or -1 if the zone ID is not available.
The ucred_getprivset() function returns the specified privilege set specified as second argument, or NULL if either the requested informa-
tion is not available or the privilege set name is invalid. The returned privilege set is valid until ucred_free() is called on the speci-
fied user credential.
The ucred_getpflags() function returns the value of the specified privilege flags from the ucred structure, or (uint_t)-1 if none was
present.
The ucred_getlabel() function returns the value of the label, or NULL if the label is not available. The returned label is valid until
ucred_free() is called on the specified user credential. This function is available only if the system is configured with Trusted Exten-
sions.
The ucred_free() function frees the memory allocated for the specified user credential.
The ucred_size() function returns sizeof(ucred_t). This value is constant only until the next boot, at which time it could change. The
ucred_size() function can be used to determine the size of the buffer needed to receive a credential option with SO_RECVUCRED. See
socket.h(3HEAD).

RETURN VALUES

See DESCRIPTION.

ERRORS

The ucred_get() function will fail if:
EAGAIN There is not enough memory available to allocate sufficient memory to hold a user credential. The application can try again
later.
EACCES The caller does not have sufficient privileges to examine the target process.
EMFILE The calling process cannot open any more files.
ENFILE
ENOMEM The physical limits of the system are exceeded by the memory allocation needed to hold a user credential.
ESRCH The target process does not exist.
The ucred_getprivset() function will fail if:
EINVAL The privilege set argument is invalid.
The ucred_getlabel() function will fail if:
EINVAL The label is not present.
The ucred_geteuid(), ucred_getruid(), ucred_getsuid(), ucred_getegid(), ucred_getrgid(), ucred_getsgid(), ucred_getgroups(),
ucred_getpflags(), ucred_getprivset(), ucred_getprojid(), ucred_getpid(), and ucred_getlabel() functions will fail if:
EINVAL The requested user credential attribute is not available in the specified user credential.